/Engine/Plugins/Editor/AssetSearch/Source/Public/IAssetIndexer.h
If your package contains a nested asset, such as the Blueprint stored in Level/World packages, it would returnUBlueprint's class in the array. This is only important if you use IndexNestedAsset.
virtual void GetNestedAssetTypes ( [TArray](API\Runtime\Core\Containers\TArray)< [UClass](API\Runtime\CoreUObject\UObject\UClass) * > & OutTypes ) const